The conventional concentric pass-type muffler includes an outer casing having its ends enclosed by heads, and an inlet tube, which is connected to the exhaust pipe, is mounted on one head and an outlet tube is mounted in the opposite head. A generally cylindrical inner body is disposed in spaced relation within the outer casing and a baffle or flange is disposed centrally of the inner body to prevent the flow of gas directly through the inner body.
In the conventional concentric pass-type muffler, annular flanges connect the ends of the inner body to the outer casing, and the flanges are provided with openings for the passage of the exhaust gas.
The exhaust gas entering the inlet tube enters the inner body and is defflected rearwardly by the central baffle, and then passes through the annular space between the inner body and the casing to the outlet tube for discharge to the exterior.